1. Field of the Invention
The invention pertains to a communication interface. More particularly, a communication interface between at least two communication buses using two different communication protocols.
2. Description of the Related Art
In the world of multimedia, data transfers between two or more appliances are becoming ever more numerous. The appliances concerned may be mass-market products such as video recorders, televisions, DVD readers, HiFi systems and the like or belong to the computing world and in particular to the world of personal computers (hereinbelow PC). The tendency at present is to make all the appliances intercommunicate. However, the transfer of data requires bigger or smaller throughputs depending on the type of appliance and depending on the type of data. Communication protocols that are more or less dedicated to the various appliances or types of appliances are used. At present, the only appliance that is truly interconnectable with substantially all the others is the PC, if the latter has a specific interface for each communication protocol.
However, certain personal computers, of portable type, have a reduced physical size which does not necessarily allow the integration of a new communication interface and they do not necessarily have all the communication interfaces available on the market.
Moreover, certain appliances are rather more dedicated to the computing world and others rather more dedicated to the world of mass-market products and it is difficult to interconnect appliances belonging to these two worlds without going by way of a PC.
At present, if one wishes to interface a device operating according to a communication protocol dedicated to the world of the PC to another device dedicated to the world of mass-market products, the interfacing is done by way of a PC, such as, for example, represented diagrammatically in FIG. 1. The PC represented comprises mainly a central processing unit (CPU) 1 having a central memory 2 coupled to the CPU 1 by a bus 3 and having a first communication interface 4 making it possible to communicate according to a first protocol and a second communication interface 5 making it possible to communicate according to a second protocol. A PC thus equipped allows a dialogue to be conducted between two appliances operating respectively according to the two protocols, for example the universal serial bus protocol, better known by the name of USB standard (standing for Universal Serial Bus) and the second protocol being, for example, the IEEE 1394 protocol. A message received in compliance with one of the protocols by one of the interfaces 4 or 5 causes the issuing of an interrupt destined for the CPU 1 which will search for a subprogram previously loaded into the central memory 2. The subprogram will make it possible to temporarily store the data received in the memory 2, then to send them to the other interface 5 or 4 so as to retransmit them according to the other protocol.
As indicated previously, the PC must be furnished with a specific subprogram for carrying out the transcoding between the two protocols. Such a subprogram then neutralizes the use of the communication interfaces 4 and 5 allowing the PC to dialogue by way of these interfaces. It is then necessary for a user to have a minimum of knowledge to be able to change the parameter settings of these interfaces 4 and 5 depending on the use that one wishes to make thereof.
This state of the art renders a simple interconnection between, for example, a music player and a digital video recorder relatively complex. Moreover, not everybody has his own PC.